445 research outputs found
Rethinking Shelving: Making Your Children’s Collections User-Friendly
No full textIt was the princesses that did it. About five years ago it seemed like every day a different little girl would come up to the children’s desk and want help finding picture books about princesses. I could do pretty well with trucks and trains because I knew enough books by author and could jump from Barton to Crews to McMullen until I found one. But I only knew a few princess books, and they were always checked out. And that was the final straw that led us to create our “Picture Book Topics” section. Soon we had a new “Pink” section filled with princesses, mermaids, and stories about girls who like sparkly things. It became and remains one of the most heavily used collections in the library.
We’ve added other new sections to our children’s collection in the past five years, including leveled early readers, a “Non-Fiction Series” area, and fiction staff picks by grade level and genre. All of the changes were spurred by asking a few basic questions about what happens at the Children’s Desk:
• How do kids (and sometimes their grownups) describe the books they want?
• Do we arrange the collection in ways that match those descriptions?
• If our collection arrangement doesn’t match a user’s questions, can we change it
Experimental Techniques
No full text. In this course we will give examples for experimental techniques used in particle physics experiments. After a short introduction, we will discuss applications in silicon microstrip detectors, wire chambers, and single photon detection in Ring Imaging Cherenkov (RICH) counters. A short discussion of the relevant physics processes, mainly different forms of energy loss in matter, is enclosed. INTRODUCTION In this course we will not try to reproduce standard text books about detectors (see for example [1,2]) and descriptions of interaction with matter (a good summary can be found in [3]), covering in great details all aspects of experimental high energy physics. Due to the time restrictions (3 \Theta 50 min were assigned by the organizers for this course) we will rather discuss examples on the use of some detector families. The selection is highly biased, since the author decided to use examples he knows best, e.g. he either worked on some of the detectors directly, or they were ..
A mesoscopic approach for draping simulation of preforms manufactured by direct fibre placement
No full textEstudios para la determinación del tiempo de vida del barión doblemente-encantado + cc
No full textEl llamado Modelo Estándar de las partículas elementales no es propiamente un modelo,
es una teoría. Y de las mejores que tenemos, en la opinión de muchos físicos, la mejor de
todas sobre la naturaleza de la materia.
De acuerdo con el Modelo Estándar, leptones y quarks son partículas verdaderamente
elementales, en el sentido de que no poseen estructura interna. Las partículas que tienen
estructura interna se llaman hadrones; están constituidas por quarks: bariones cuando están
formadas por tres quarks o tres antiquarks, o mesones cuando est´an constituidas por un
quark y un antiquark1.
Hay seis leptones: electrón, mu´on, tau, neutrino del electrón, neutrino del muón y neutrino del tau y seis quarks: quark up (u), quark down (d), quark charm (c), quark strange (s),quark bottom, (b) y quark top (t). Sin embargo, los quarks tienen una propiedad llamadacolor2 y cada uno puede presentar tres colores (rojo, verde y azul). Hay, por tanto, 18 quarks.
1la antipart´ıcula del quark
2Se trata de una propiedad, no un color propiamente dicho. Rojo, verde y azul son s´olo aspectos de esaInvestigadoresEstudiante
Charcot-Marie-Tooth neuropathy type 2A: novel mutations in the mitofusin 2 gene (<it>MFN2</it>)
No full textAbstract Background Charcot-Marie-Tooth neuropathies are a group of genetically heterogeneous diseases of the peripheral nervous system. Mutations in the MFN2 gene have been reported as the primary cause of Charcot-Marie-Tooth disease type 2A. Methods Patients with the clinical diagnosis of Charcot-Marie-Tooth type 2 were screened using single strand conformation polymorphism (SSCP). All DNA samples showing band shifts in the SSCP analysis were amplified from genomic DNA and cycle sequenced. Results We analyzed a total of 73 unrelated patients with a clinical diagnosis of CMT 2. Overall, novel mutations were detected in 6 patients. c.380G>T (G127V), c.1128G>A (M376I), c.1040A>T (E347V), c.1403G>A (R468H), c.2113G>A (V705I), and c.2258_2259insT (L753fs). Conclusion We confirmed a significant role of mutations in MFN2 in the pathogenesis of Charcot-Marie-Tooth disease type 2.</p
An aerogel RICH detector for the next generation heavy-ion experiment at LHC
No full textThe ALICE collaboration is proposing a new apparatus, ALICE 3, to investigate the Quark Gluon Plasma (QGP) properties. In this context, conceptual studies for the development of a RICH detector for ALICE 3 are ongoing. The proposed baseline layout is a proximity-focusing RICH, using aerogel (refractive index n= 1.03 at λph= 400 nm) as Cherenkov radiator and a layer of Silicon Photomultipliers (SiPM) for the photon detection. A multi-layer (focusing) aerogel layout, with increasing refractive index, is also considered. If good time resolution of ≈ 20 ps can be achieved in the SiPM photons detectors, they can be able to identify charged hadrons via TOF measurements. The detector specifications and performance, obtained by means of dedicated Monte Carlo simulation, are presented. The R&D challenges related to the proposed design are also discussed
A Measurement of Lambda Polarization in Inclusive Production by Sigma- of 340- GeV/c in C and Cu Targets
No full textWe have measured the polarization of Sigma(-) beam of 340 GeV/c momentum in nuclear targets. From a sample of 9.5 millions of identified Lambda decays, polarizations were determined in the range x(F) gt 0.1 and p(t)less than or equal to1.6 GeV/c . The polarization w.r.t. the production normal is mainly positive for x(F)greater than or equal to0.3. At fixed values of x(F) , it increases with p(t) to a maximum between p(t)=0.5 and p(t)=1 GeV/c , and then decreases to zero or even negative values, in sharp contrast to the plateau above p(t)=1 GeV/c observed in inclusive Lambda production by protons
ChPT tests at NA62
No full textThe NA62 experiment at CERN SpS collected a large sample of charged kaon decays with a low intensity beam and minimum bias trigger conditions in 2007. This allowed measurements of a number of rare decays that are difficult to address in conventional high intensity experiments with highly selective trigger conditions. In particular, large samples of K± →π±γ γ and K± →e± νγ decays have been collected, allowing precision tests of the Chiral Perturbation Theory. The status and first results of these analyses are presented. © Copyright owned by the author(s)
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